I. Field if the Invention
This invention relates to apparatus for detecting or measuring movements in geological formations or other massive structures. More particularly, the invention relates to apparatus of this kind that can be used by mining engineers, geologists, construction engineers and the like to assess strains and movements in rock, building foundations and other fabricated structures.
II. Description of the Prior Art
Apparatus of this kind is used primarily for monitoring geological formations. The monitoring of such structures plays an important and necessary role in mining and in the practice of tunnelling, underground and surface excavation engineering. As part of an overall project design, instrumentation is required to improve economy and safety during the excavation development phase. A number of instruments are used in the geotechnical and mining industries to provide information about ground behaviour before, during and after excavation development. Such mining and geotechnical instrumentation typically uses electrical, vibrating wire, mechanical, hydraulic and optical systems as measuring principles. The most common rock mechanics instruments used in industry include extensometers, convergence meters, strain gauges, inclinometers, tiltmeters, crack/joint meters, stressmeters, strain cells, pressure cells, load cells, microseismic sensors and piezometers.
Most of these instruments are used to monitor ground behaviour in two dimensions. In order to overcome this limitation, users install multiple instrumentation stations and resolve data in three dimensions. Such installations are expensive and, in many applications, unfeasible.
Thus, despite the large number of instruments already available, there is still a need for apparatus that can measure rock movement in three dimensions and is nevertheless inexpensive to manufacture.
Similar problems exist for construction engineers involved in the monitoring of building foundations or massive construction projects. There is therefore a need for such apparatus in these fields.